International name - Vitamin A, in the form of a dietary supplement is also called retinol.

A fat-soluble vitamin, an essential component for healthy growth, bone and tooth tissue formation, and cell structure. It is of great importance for night vision, it is necessary to protect against infections of the tissues of the respiratory, digestive and urinary tracts. Responsible for the beauty and youthfulness of the skin, the health of hair and nails, visual acuity. Vitamin A is absorbed in the body in the form of retinol, which is found in liver, fish oil, egg yolk, dairy products and added to margarine. Carotene, which is converted into retinol in the body, is found in many fruits and vegetables.

Discovery history

The first prerequisites for the discovery of Vitamin A and the consequences of its insufficiency appeared as early as 1819, when the French physiologist and psychologist Magendie noticed that dogs that receive poor nutrition are more likely to get corneal ulcers and have a higher mortality rate.

In 1912, British biochemist Frederick Gowland Hopkins discovered hitherto unknown substances in milk that did not look like fats, carbohydrates, or proteins. Upon closer examination, it turned out that they contributed to the growth of laboratory mice. Hopkins received the Nobel Prize in 1929 for his discovery. In 1917, Elmer McCollum, Lafayette Mendel, and Thomas Burr Osborne also saw similar substances when studying the role of dietary fats. In 1918, these "additional substances" were found to be fat-soluble, and in 1920 they were finally given the name Vitamin A.

Foods rich in vitamin A

Estimated availability in 100 g of product

Daily requirement for vitamin A

Recommendations for daily intake of vitamin A are based on the amount needed to provide a supply of retinol for several months in advance. This reserve maintains the normal functioning of the body and ensures healthy functioning. reproductive system, immunity, vision and gene activity.

In 1993, the European Scientific Committee on Nutrition published data on the recommended intake of vitamin A:

Many European nutrition committees, such as the German Nutrition Society (DGE), recommend 0.8 mg (800 mcg) of vitamin A (retinol) for women and 1 mg (1000 mcg) for men per day. Since vitamin A plays a significant role in the normal development of the embryo and newborn, pregnant women are advised to take 1.1 mg of vitamin A starting from the 4th month of pregnancy. Women who are breastfeeding should receive 1.5 mg of vitamin A per day.

In 2015, the European Food Safety Authority (EFSA) established that the daily intake of vitamin A should be 750 mcg for men, 650 mcg for women, for newborns and children - from 250 to 750 mcg of the vitamin per day, taking into account age . During pregnancy and lactation, the additional amount of the vitamin that should be ingested due to the accumulation of retinol in the tissues of the fetus and mother, as well as the intake of retinol in breast milk, was indicated at 700 and 1,300 mcg per day, respectively.

In 2001, the American Food and Nutrition Council also set the recommended intake for vitamin A:

As we can see, although the amount varies according to different organizations, the approximate daily intake of vitamin A remains at the same level.

The need for vitamin A increases with:

1. 1 weight gain;
2. 2 strenuous physical labor;
3. 3 work in night shifts;
4. 4 participation in sports competitions;
5. 5 stressful situations;
6. 6 work in conditions of improper lighting;
7. 7 additional eye strain from monitors;
8. 8 pregnancy, breastfeeding;
9. 9 problems with the gastrointestinal tract;
10. 10 SARS.

Physical and chemical properties

Vitamin A is a fat-soluble vitamin that is part of a group of molecules with a similar structure - retinoids - and occurs in several chemical forms: aldehydes (retinal), alcohol (retinol) and acid (retinoic acid). In animal products, the most abundant form of vitamin A is an ester, primarily retinyl palmitate, which is synthesized to retinol in the small intestine. Provitamins - biochemical precursors of vitamin A - are present in plant products, they are components of the carotenoids group. Carotenoids are organic pigments found naturally in plant chromoplasts. Less than 10% of the 563 carotenoids known to science can be synthesized into vitamin A in the body.

Vitamin A is a fat-soluble vitamin. This is the name of a group of vitamins, for the assimilation of which the body needs the intake of dietary fats, oils or lipids. These include, for example, cooking oils, nuts, fish, meat, avocados.

Vitamin A dietary supplements are often available as oil-filled capsules to ensure that the vitamin is fully absorbed by the body. People who don't eat enough dietary fat are more likely to be deficient in fat-soluble vitamins. Similar problems can occur in people with poor absorption of fats. Fortunately, fat-soluble vitamins naturally occur naturally in foods that contain fat. Thus, with a good diet, the lack of such vitamins is rare.

In order for vitamin A or carotene to enter the bloodstream in the small intestine, it is necessary that they, however, like other fat-soluble vitamins, are combined with bile. If the food at this moment contains little fat, then little bile is secreted, which leads to malabsorption and loss of up to 90 percent of carotene and vitamin A with feces.

Approximately 30% of beta-carotene is absorbed from plant foods, about half of beta-carotene is converted into vitamin A. From 6 mg of carotene, 1 mg of vitamin A is formed in the body, so the conversion ratio of the amount of carotene to the amount of vitamin A is 1:6.

Useful properties of vitamin A

Vitamin A performs several functions in the body. The most famous is its effect on vision. Retinyl ester is transported to the retina, which is located inside the eye, where it is processed into a substance called 11-cis-retinal. Further, 11-cis-retinal is in the rods (one of the photoreceptors), where it combines with the protein opsin and forms the visual pigment "rhodopsin". Rods containing rhodopsin can detect even very small amounts of light, making them essential for night vision. The absorption of a photon of light catalyzes the transformation of 11-cis-retinal back to all-trans-retinal and results in its release from the protein. This sets off a chain of events leading to the generation of an electrochemical signal to the optic nerve, which is processed and interpreted by the brain. Lack of retinol available to the retina leads to impaired dark adaptation, known as night blindness.

Vitamin A in the form of retinoic acid plays an important role in the regulation of gene expression. Once retinol is taken up by the cell, it can be oxidized to retinal, which is oxidized to retinoic acid. Retinoic acid is a very powerful molecule that binds to various nuclear receptors to initiate or inhibit gene expression. Through the regulation of the expression of specific genes, retinoic acid plays an important role in cell differentiation, one of the most important physiological functions.

Vitamin A is needed for the normal functioning of the immune system. Retinol and its metabolites are needed to maintain the integrity and function of skin cells and mucous membranes (respiratory, digestive and urinary systems). These tissues serve as a barrier and are the body's first line of defense against infections. Vitamin A plays a central role in the development and differentiation of white blood cells, lymphocytes, which are key agents in the immune system's response.

Vitamin A is indispensable for embryonic development, being directly involved in the growth of limbs, the formation of the heart, eyes and ears of the fetus. In addition to this, retinoic acid affects the expression of the gene responsible for growth hormone. Both deficiency and excess of vitamin A can cause birth defects.

Vitamin A is used for the normal development of stem cells into red blood cells. In addition, vitamin A probably improves the mobilization of iron from reserves in the body, directing it to the developing red blood cell. There, iron is incorporated into hemoglobin, the oxygen carrier in red blood cells. Vitamin A metabolism is thought to interact with zinc and iron in several ways. Zinc deficiency can lead to a decrease in the amount of transported retinol, a decrease in the release of retinol in the liver, and a decrease in the conversion of retinol to the retina. Vitamin A supplements have a beneficial effect on iron deficiency (anemia) and improve iron absorption in children and pregnant women. The combination of vitamin A and iron appears to treat anemia more effectively than supplemental iron or vitamin A alone.

Recent studies have shown that vitamin A, carotenoids, and provitamin A carotenoids may be effective antioxidants in preventing heart disease. The antioxidant activity of vitamin A and carotenoids is provided by the hydrophobic chain of polyene units, which can quench singlet oxygen (molecular oxygen with higher activity), neutralize thiyl radicals, and stabilize peroxyl radicals. In short, the longer the polyene chain, the higher the stability of the peroxyl radical. Because of their structure, vitamin A and carotenoids can be oxidized with increasing O2 tension and thus are the most effective antioxidants at low oxygen tensions, which are characteristic of the physiological levels found in tissues. Overall, epidemiological evidence suggests that vitamin A and carotenoids are important dietary factors in reducing the incidence of heart disease.

The European Food Safety Authority (EFSA), which provides scientific advice to policy makers, has confirmed that the following health benefits have been seen with vitamin A intake:

• normal cell division;
• normal development and functioning of the immune system;
• maintaining the normal condition of the skin and mucous membranes;
• maintaining vision;
• normal iron metabolism.

Vitamin A has a high compatibility with vitamins C and E and the minerals iron and zinc. Vitamins C and E protect vitamin A from oxidation. Vitamin E increases the absorption of vitamin A, but only in cases where vitamin E is consumed in a small amount. A high content of vitamin E in the diet, in turn, impairs the absorption of vitamin A. Zinc helps the absorption of vitamin A, taking part in its conversion to retinol. Vitamin A enhances the absorption of iron and influences the utilization of the iron reserve present in the liver.

Vitamin A also pairs well with vitamins D and K2, magnesium, and dietary fat. Vitamins A, D, and K2 work synergistically to support immune health, promote adequate growth, maintain bone and tooth health, and protect soft tissues from calcification. Magnesium is essential for the production of all proteins, including those that interact with vitamins A and D. Many of the proteins involved in vitamin A metabolism and the receptors for both vitamins A and D only function properly in the presence of zinc.

Vitamins A and D also work together to regulate the production of certain vitamin dependent proteins. Once vitamin K activates these proteins, they help mineralize bones and teeth, protect arteries and other soft tissues from abnormal calcification, and protect against cell death.

Foods containing vitamin A are best consumed with foods that contain “healthy” fat. For example, spinach, which contains a high content of vitamin A and lutein, is recommended to be combined with avocado. The same goes for lettuce and carrots, which pair well with avocados in salads. As a rule, products of animal origin, rich in vitamin And they already contain a certain amount of fat, sufficient for its normal absorption. As for vegetables and fruits, it is recommended to add a small amount vegetable oil in a salad or freshly squeezed juice - this way we will be sure that the body will receive the necessary vitamin in full.

It is worth noting that the best source of vitamin A in particular, as well as other useful substances, is a balanced diet and natural products, not dietary supplements. When using vitamins in medicinal form, it is very easy to make a mistake with the dosage and get more than the body needs. And an excess of one or another vitamin or mineral in the body can have very serious consequences. The risk of developing oncological diseases may increase, the general condition of the body may worsen, metabolism and the functioning of organ systems may be disturbed. Therefore, the use of vitamins in tablets should be carried out only if necessary and after consulting a doctor.

Application in medicine

Intake of a large amount of vitamin A is prescribed in such cases:

• with vitamin A deficiency, which can occur in people with protein deficiency, diabetes, an overactive thyroid gland, fever, liver disease, cystic fibrosis, or an inherited disorder called abelatipoproteinemia.
• in breast cancer. Premenopausal women with a family history of breast cancer who consume high levels of vitamin A in their diet are thought to reduce their risk of developing breast cancer. It is not known whether taking vitamin A as a dietary supplement has a similar effect.
• with cataracts. Studies show that a high intake of vitamin A in the diet leads to a reduced risk of developing cataracts.
• with diarrhea caused by HIV. Taking vitamin A along with conventional medications appears to reduce the risk of death from diarrhea in HIV-infected children with vitamin A deficiency.
• with malaria. Taking vitamin A by mouth reduces the symptoms of malaria in children under 3 years of age in areas where malaria is common.
• with measles. Taking vitamin A by mouth reduces the risk of complications or death from measles in children who have measles and are deficient in vitamin A.
• with precancerous lesions in the mouth (oral leukoplakia). Research shows that taking vitamin A can help treat precancerous lesions in the mouth.
• in recovery after laser eye surgery. Taking vitamin A orally along with vitamin E improves healing after laser eye surgery.
• with complications after pregnancy. Taking vitamin A reduces the risk of diarrhea and fever after pregnancy in malnourished women.
• with complications during pregnancy. Oral vitamin A supplementation reduces the risk of death and night blindness during pregnancy in malnourished women.
• in eye diseases affecting the retina (retinitis pigmentosa). Studies show that vitamin A supplementation can slow the progression of eye diseases that cause damage to the retina.

The pharmacological form of vitamin A can be different. In medicine, it is found in the form of dragees, drops for oral administration, drops for oral administration in oil form, capsules, oily solution for intramuscular administration, oily solution for oral administration, in the form of coated tablets. Vitamin A is taken for prevention and for medicinal purposes, as a rule, 10-15 minutes after eating. Oil solutions are taken in case of malabsorption in the gastrointestinal tract or in severe illness. In cases where long-term treatment is necessary, the solution for intramuscular injection is combined with capsules. In pharmacology, the amount of vitamin A is often indicated in International Units. With mild to moderate beriberi, adults are prescribed 33 thousand International Units per day; with hemeralopia, xerophthalmia - 50-100 thousand IU / day; children - 1-5 thousand IU / day, depending on age; for skin diseases in adults - 50-100 thousand IU / day; children - 5-20 thousand IU / day.

Traditional medicine advises the use of vitamin A as a remedy for flaky and unhealthy skin. To do this, it is recommended to consume fish oil, liver, butter and eggs, as well as vegetables rich in vitamin A - pumpkin, apricot, carrots. good remedy make up for the deficiency is freshly squeezed carrot juice with the addition of cream or vegetable oil. Another folk remedy obtaining a vitamin is considered a decoction of tubers high - it is used as a tonic, tonic and antirheumatic agent. Also a valuable source of vitamin A, as well as other useful substances, are flax seeds, which are consumed orally and as part of external masks, ointments and decoctions. According to some reports, a high amount of vitamin A is contained in the tops of carrots, even more than in the fruit itself. It can be used in cooking, as well as making a decoction, which is used internally as a course for a month.

Latest scientific research on vitamin A:

Researchers at the Case Western Reserve University School of Medicine have found that an uncontrolled metabolism of vitamin A in the gut can cause dangerous inflammation. The discovery establishes a link between dietary composition and inflammatory diseases such as Crohn's disease and irritable bowel syndrome.

Researchers have found a branch point in the vitamin A metabolic pathway that depends on a specific protein called ISX. The beginning of the journey is beta-carotene, a pigmented, highly nutritious substance, thanks to which the color of sweet potatoes and carrots is formed. Beta-carotene is converted to vitamin A in the digestive tract. From there, the largest proportion of vitamin A is delivered to other tissues, providing good vision and other important functions. When studying mice that had had ISX removed, scientists noticed that this protein helps the body balance this process. Protein helps the small intestine determine how much beta-carotene it needs to meet the body's need for vitamin A. Immune cells rely on this control mechanism to properly respond to foods entering the small intestine. This provides an effective barrier against potential food hazards. Researchers have found that when ISX is absent, immune system cells in the digestive tract overreact to the beta-carotene-rich diet. Their results prove that ISX is the main link between what we eat and gut immunity. The scientists concluded that removing the ISX protein speeds up the expression of the gene that converts beta-carotene to vitamin A by 200 times. Because of this, ISX-deleted mice received an excess of vitamin A and began to convert it into retinoic acid, a molecule that regulates the activity of many genes, including those that form immunity. This caused localized inflammation as immune cells filled the area in the gut between the stomach and colon and began to multiply. This severe inflammation spread to the pancreas and caused the mice to become immunodeficient.

A recent study shows that vitamin A increases the activity of insulin-producing β-cells. Scientists have found that insulin-producing beta cells have a high number of receptors on their surface that are sensitive to vitamin A. Researchers believe that the reason for this is that vitamin A plays great importance in the development of beta cells in the first stages of life, as well as for proper and functioning during the rest of life, especially during pathophysiological conditions - that is, in certain inflammatory diseases.

To study the importance of vitamin A in diabetes, the researchers worked with insulin cells from mice, healthy people, and people with type 2 diabetes. The scientists fragmentarily blocked the receptors and gave the patients some sugar. They saw that the cells' ability to secrete insulin was deteriorating. The same trend could be observed when comparing insulin cells from donors with type 2 diabetes. The cells of patients with type 2 diabetes were less able to produce insulin compared to those of people without diabetes. Scientists have also discovered that the resistance of beta cells to inflammation is reduced in the absence of vitamin A. When it is completely absent, the cells die. This study may also be relevant for some types of type 1 diabetes, where beta cells are poorly developed in the early stages of life. “As it became clear after research with animals, newborn mice need vitamin A for the full development of their beta cells. We are pretty sure that the same thing happens in humans. Children need to get the right amount of vitamin A in their diet,” said Albert Salehi, senior researcher at the Diabetes Center at Lund University in Sweden.

Scientists at the University of Lund in Sweden have discovered a previously unexplored effect of vitamin A on human embryonic development. Their research demonstrates that vitamin A has an effect on the formation of blood cells. The signaling molecule known as retinoic acid is a vitamin A derivative that helps determine how different types tissues in the growing fetus.

An unprecedented study by Prof. Niels-Bjarn Woods' laboratory at the Lund Stam Cell Center in Sweden showed the effect of retinoic acid on the development of red blood cells, white blood cells and platelets from stem cells. Under laboratory conditions, stem cells were influenced by certain signaling molecules, transforming into hematopoietic cells. Scientists have noticed that high levels of retinoic acid rapidly lower the number of blood cells produced. The decrease in retinoic acid, in turn, increased the production of blood cells by 300%. Despite the fact that vitamin A is needed for the normal course of pregnancy, it has been found that an excess of vitamin A harms the embryo, introducing the risk of developing a malformation or stopping the pregnancy. In view of this, pregnant women are strongly advised to control the intake of foods containing a large amount of vitamin A in the form of retinoids, such as, for example, liver. “The results of our study show that vitamin A in large quantities negatively affects blood formation. This suggests that pregnant women should additionally avoid excessive intake of vitamin A,” says Niels-Bjarn Woods.

This is one of the main components that provide a healthy and toned skin. With the intake of a sufficient amount of vitamin, you can forget about such problems as skin laxity, age spots, acne, acne, dryness.

Vitamin A in its pure, concentrated form can be easily found in pharmacies, in the form of capsules, oil solutions and ampoules. It is worth remembering that this is a fairly active component, so it should be used with caution, and preferably after 35 years. Cosmetologists advise making masks containing vitamin A during the cold season and once a month. If there are contraindications to the use of pharmacy vitamin A as part of masks, you can replace it with natural products that are rich in this vitamin - viburnum, parsley, spinach, egg yolks, dairy products, pumpkin, carrots, fish oil, algae.

There are many recipes for masks with vitamin A. They often contain fat-containing substances - olive oil, fat sour cream, burdock oil. Vitamin A (oil solution and retinol acetate) has good compatibility with aloe juice, oatmeal and honey. To eliminate mimic wrinkles and bruises under the eyes, you can use a mixture of vitamin A and any vegetable oil, or Aevit, which already contains both vitamin A and vitamin E. A good preventive and therapeutic remedy for acne is a mask with ground lentils, vitamin A in an ampoule or a small amount of zinc ointment, applied 2 times a month. In the presence of allergic reactions, open wounds and skin lesions, any of its diseases, you should refrain from using such masks.

Vitamin A is also good for nail health when mixed with other ingredients. For example, you can prepare a hand mask with liquid vitamins A, B, and D, oily hand cream, coconut oil, lemon juice, and a drop of iodine. This mixture should be applied to the skin of the hands and nail plates, massaged for 20 minutes and left to be absorbed. Regular implementation of this procedure will improve the condition of nails and hands.

The impact of vitamin A on the health and beauty of hair should not be underestimated. It can be added to shampoos (immediately before each procedure, in order to avoid oxidation of the substance when added to a whole package of shampoo), to masks - to increase shine, softness and strength of hair. As in face masks, vitamin A is recommended to be combined with other ingredients - vitamin E, various oils, decoctions (chamomile, horsetail), starch (for softness), mustard or pepper (to accelerate hair growth). These products should be used with caution for those who are allergic to pharmacy vitamin A and for those whose hair is prone to increased oiliness.

Vitamin A in animal, crop and industry

Found in green grass, alfalfa, and some fish oils, vitamin A, otherwise known as retinol, is one of the nutrients essential for poultry health. Vitamin A deficiency leads to poor plumage along with weakness, eye and beak problems, up to and including damage. Another important factor for production - lack of vitamin A can slow down growth.

Vitamin A has a relatively short shelf life and, as a result, dry foods stored for extended periods of time may not contain sufficient amounts of the vitamin. After illness or stress, the immune system of birds is very weak. By adding a short course of vitamin A to feed or water, further illness can be prevented, as without sufficient vitamin A, birds are susceptible to a number of harmful pathogens.

Vitamin A is also essential for the healthy growth of mammals, to maintain a good appetite, coat condition and immunity.

• it is the first vitamin discovered by man;
• polar bear liver is so rich in vitamin A that eating a whole liver can be fatal to humans;
• approximately 259 to 500 million children lose their sight every year due to vitamin A deficiency;
• in cosmetics, vitamin A is most often found under the names retinol acetate, retinyl linoleate and retinyl palmitate;
• rice fortified with vitamin A, developed about 15 years ago, could prevent hundreds of thousands of cases of blindness in children. But due to concerns about genetically modified foods, it was never put into production.

Dangerous properties of vitamin A, its contraindications and warnings

Vitamin A is quite resistant to high temperatures, but is destroyed in direct sunlight. Therefore, it is necessary to store vitamin-rich foods, as well as medical nutritional supplements, in a dark place.

Signs of Vitamin A Deficiency

Vitamin A deficiency usually results from inadequate intake of foods high in vitamin A, beta-carotene, or other provitamin A carotenoids; which are metabolized into vitamin A in the body. In addition to dietary problems, excess alcohol intake and malabsorption can be the cause of vitamin A deficiency.

The earliest sign of vitamin A deficiency is blurred vision in the dark, or night blindness. Severe or prolonged vitamin A deficiency causes changes in corneal cells that eventually lead to corneal ulcers. Vitamin A deficiency among children in developing countries is the leading cause of blindness.

Vitamin A deficiency is also associated with immunodeficiency, decreasing the ability to fight infections. Even children with mild vitamin A deficiency have a higher incidence of respiratory disease and diarrhea, as well as a higher mortality rate from infectious diseases (especially measles) compared to children with adequate vitamin A intake. In addition, vitamin A deficiency can cause impaired growth and bone formation in children and adolescents. In smokers, vitamin A deficiency can contribute to chronic obstructive pulmonary disease (COPD) and emphysema, both of which are thought to increase the risk of lung cancer.

Signs of Too Much Vitamin A

Acute vitamin A hypervitaminosis caused by very high doses of retinol, which is rapidly absorbed and slowly excreted from the body, is relatively rare. Symptoms include nausea, headache, fatigue, loss of appetite, dizziness, dry skin, and swelling of the brain. There are studies that prove that prolonged excess of vitamin A in the body can lead to the development of osteoporosis. Some synthetic retinol derivatives (eg, tretinate, isotretinoin, tretinoin) may cause fetal defects and therefore should not be used during pregnancy or when trying to conceive. In such cases, beta-carotene is considered the safest source of vitamin A.

Results from the Beta-Carotene and Retinol Efficacy Study (CARET) suggest that long-term vitamin A (retinol) and beta-carotene supplementation should be avoided in the long term in people at high risk of developing lung cancer, such as smokers and people exposed to asbestos.

Interaction with other drugs

Vitamin A, which has already entered the bloodstream, begins to quickly break down if the body lacks vitamin E. And if there is a lack of vitamin B4 (choline), then vitamin A is not stored for future use. Antibiotics are thought to somewhat reduce the effects of vitamin A. In addition, vitamin A can increase the effects of a substance called isotretinoin and lead to severe side effects.

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Content

Vitamin A is not just in the first place in the general alphabetical list of vitamins: it is involved in almost all the main functions of the body, improves vision, strengthens the immune system. Vitamin A is also important for the skin. Let's find out what functions vitamin A performs, how to take it and what are the contraindications to taking it.

What is vitamin A good for the body

Vitamin A regulates the process of protein production by the body, contributes to the normalization of metabolism, strengthens the immune system, effectively resists viral infections, and helps with wound healing. In addition, it makes the skin of women and men elastic, smooth, relieves skin diseases. Retinol is also useful for vision, so people who spend a lot of time in front of the screen should include it in their diet. For example, a product such as carrots will protect the mucous membrane of the eye from drying out and relieve you of the feeling of "sand" in the eyes. And retinol will help you see better at night.

It must be present in the diet of infants and older children, because the components of the vitamin play an important role in the formation of bones, joints and teeth, accelerating cell growth. Retinol also has a positive effect on the functioning of the organs of the respiratory and digestive systems, therefore, for smokers, vitamin A is of particular importance.

For Women's Health

Retinol is of great importance for women. The breast, which consists primarily of adipose tissue, is highly dependent on the balance of fat-soluble vitamins. One of them is retinol. The work of the cells responsible for lactation is regulated by chemical processes occurring in the mammary glands. Numerous studies have proven that lactating and pregnant women need to take many additional vitamins, including retinol.

What vitamin A helps for is for a spectacular appearance women. Retinol is directly involved in the normalization of the lipid balance of the body. This component improves the condition of hair, nails, skin, improves vision and strengthens the immune system. Retinol is an ingredient in professional skin care creams - it makes it supple, firm, smoothes fine wrinkles. Retinol can be a great alternative to many beauty products. At least, the reviews on the use of vitamin A for cosmetic purposes are entirely positive.

With vitamin A deficiency female body girls lose weight, have problematic dry skin, they are worried about bouts of depression, nausea, sleep problems. The mucous membrane of the eyes with a deficiency of retinol is not sufficiently moisturized, the eyes hurt. Subsequently, the development of cataracts is possible. A lack of retinol can make it difficult for a woman to get pregnant, and the gestation process will be difficult. The fetus will gain mass slowly, in the worst case, birth defects. Finally, gynecological diseases may develop: cervical erosion, leukoplakia.

For kids

Vitamin deficiency in a child's body can lead to progressive blindness, conjunctivitis, reduced resistance to infectious (including colds) diseases, their frequent complications in the form of pneumonia or bronchitis, growth retardation, diseases of the digestive tract. Balanced diet and regular intake of vitamin A will help the body cope with such ailments. Retinol is good for the teeth and bones of newborns and young children - it accelerates their growth.

For weight loss

Vitamin A intake does not directly affect weight loss. On the other hand, experts recommend consuming the required dose of vitamin A orally for people involved in sports or fitness. Retinol speeds up metabolism, increases stamina and helps the body recover much faster from workout to workout. That is, you get the opportunity to practice more often and with maximum efficiency. And effective training will help to achieve quick results in losing weight, after which - to maintain the desired figure.

Why is vitamin A useful in cosmetology

The benefits of vitamin A are not only in healing the body from the inside, but also in a positive effect on the condition of the skin, nails, and hair. The widespread use of retinol by cosmetologists seems logical. The beneficial properties of vitamin A are known to millions of women who are trying to make their appearance flawless and use it both for the skin of the face and for the heels (for example, to heal cracks). Let's learn about the areas and features of the use of retinol in cosmetology.

Liquid vitamin for the face

Retinol has excellent efficacy in the treatment of various skin ailments, improves skin condition. If vitamin A is not enough in the body, wrinkles appear, the skin becomes dry, and the face looks unhealthy. Liquid retinol is used to treat:

• Chronic form of dermatosis.
• Psoriasis.
• Acne.
• Furunculosis.
• Psoriasis.
• seborrheic eczema.
• Inflammation of the oral mucosa.

Retinol has antioxidant properties, thanks to which the skin of the face becomes more resistant to sunlight and other adverse environmental factors. That is, liquid vitamin A keeps you young and makes you more attractive. This substance, included in the composition of masks, helps to smooth out wrinkles in a natural way, improve blood circulation, and natural skin regeneration. Beauticians claim that retinol is a great alternative to much more expensive cosmetic products, surpassing them in terms of effectiveness.

For eyelids and eyelashes

If you want to become the owner of beautiful, long, elastic and, most importantly, natural eyelashes, be sure to use products containing vitamin A. Retinol is needed for the synthesis of keratin, a substance that accelerates the growth of eyelashes, helping them recover faster from damage, increasing their elasticity. We offer an effective cosmetic recipe: mix vitamin A with castor oil (proportion 1:3) and apply the resulting mixture on the eyelashes every evening for 3-5 minutes. After this time, gently wipe them with a sponge.

The benefits of hair masks

Enrichment of hair with retinol, included in the masks, helps to improve their condition. Thanks to retinol, the curls are strengthened, become elastic, smooth, look healthy, alive. With a deficiency of this substance - brittle, dry, often fall out. To strengthen curls, you need to rub retinol and other useful vitamins fingertips into the roots of the hair or apply to their ends. Remember that masks should be applied to washed, slightly damp curls. The cap will ensure more effective absorption of useful components.

For hands and nails

Devoting a lot of time to facial skin care, the fair sex often make the mistake of forgetting about the skin of their hands. After all, it is also exposed to external influences (sudden temperature fluctuations, ultraviolet radiation, household chemicals), from which it begins to peel off, dry out, crack, and look unkempt. Diet, work, and the general condition of the body have a great influence on the appearance of the skin of the hands.

Retinol is a natural ingredient that helps to cope with the above problems. Note that it also has a positive effect on the nail plates, strengthening them, making them smoother, accelerating growth and preventing delamination. Eat more fresh vegetables that are rich in retinol, and foods that are a source of animal proteins - dairy products, sea fish. Proteins provide better absorption of retinol by the body. It is noteworthy that the rate of nail growth in vegetarians is very low.

We will offer effective method hand skin care. Purchase oil solutions of vitamins A, E at the pharmacy and rub them in regularly. In parallel, take retinol in capsules or tablets (not exceeding the allowable dosage). Beauticians recommend another way, based on the enrichment of regular hand cream with retinol. It is not difficult to do this: just pour the hand cream into a clean empty container, add the oil solution there, mix. Use like a normal cream.

How to take vitamin A capsules correctly

When taking vitamin A capsules, it is important not to violate the dosage prescribed for you, because an excess of this substance in the body can be no less harmful than a lack of retinol. The average daily requirement for an adult in retinol is 1 mg, for a child - from 400 to 800 mcg. Note that vitamin A is available in capsules containing 33,000, 50,000 or 100,000 IU (international units).

Interestingly, simply consuming the right amount of capsules is not enough to eliminate the body's deficiency in vitamin A. You also need to know exactly how to use retinol. So, the capsules should be drunk 2 times a day - in the morning and in the evening, moreover, exactly 10 minutes after the end of the meal. The reason is that just after such a time, the stomach extracts components from food that promote the absorption of vitamin A. Without them, retinol will not be effectively absorbed.

Contraindications to the use of retinol

Retinol, according to the instructions, is not recommended if you have been diagnosed with cholelithiasis, pancreatitis, hypersensitivity to the substance. A contraindication is also the period of pregnancy, especially the first 3 months after fertilization. You should be careful in chronic diseases of the heart, kidneys. Other contraindications for taking retinol: cirrhosis of the liver, hepatitis. Be sure to comply daily allowance children, the elderly, nursing mothers.

Interaction of vitamin A with other substances

Vitamin E is known to protect retinol from rapid oxidation in the intestines and body tissues. That is, if your diet does not have enough foods containing vitamin E, the body will not effectively absorb retinol. The solution is a complex intake of both vitamins. Zinc deficiency also interferes with the conversion of vitamin A into active ingredients. Moreover, there is an inverse relationship. That is, these substances are interconnected.

Mineral oils are able to dissolve fat-soluble components: then vitamin A passes through the intestines, but is not absorbed by its walls. Therefore, the regular use of mineral oils leads to a deficiency of retinol in the body, even if there is plenty of this substance in the products you consume. The way out will be a temporary rejection of mineral oils.

Finally, it should be noted that for good absorption of retinol, the presence of a sufficient amount of fats and proteins in the daily diet is mandatory. The body normally extracts vitamin A dissolved in dietary fats. It should also be remembered that while taking retinol, it is necessary to exclude from your diet. alcoholic drinks. Neglect of this rule is fraught with the likelihood of liver damage.

Vitamin A belongs to the group of fat-soluble compounds (lipovitamins). It is able to be deposited in the body, mainly in the liver.

According to the WHO, with hypovitaminosis in vitamin A, none of the food products can cover its deficiency, and therefore the intake of retinol in the form of pharmacological preparations is required.

Vitamin A is formed in the body from provitamins - "carotenoids" coming from outside. The term comes from carrot (carrot, English), since these precursor substances were first discovered in carrots. Related compounds are present in a wide range of vegetables and fruits (especially yellow, red and orange), as well as in algae and certain types of fungi.

Currently, more than half a thousand carotenoids are known to science.

The most common of these are:

• a-, b- and d-carotene;
• zeaxanthin;
• lutein;
• lycopene.

Beta-carotene undergoes oxidation in the human liver, and, splitting, forms vitamin A.

The unit of measurement for retinol is 1 ER, which corresponds to 1 µg of retinol, 6 µg of b-carotene, or 12 µg of other carotenoids.

1 mcg is 3.33 IU for retinol or 10 IU for b-carotene.

Important:it has been experimentally proven that beef, skimmed milk, and cereals contain insufficient amounts of carotene and retinol, i.e., they cannot serve as full-fledged sources of vitamin A.

Animal foods containing vitamin A:

• beef liver;
• Cod liver;
• fish fat;
• sea ​​fish caviar;
• whole milk;
• cream;
• egg yolk.

Plant Sources:

• carrot;
• tomatoes;
• pepper ("Bulgarian" and hot cayenne);
• spinach;
• broccoli;
• parsley;
• parsley;
• peas;
• soya beans;
• apples;
• (kelp seaweed).

Important:in large quantities, provitamin A is present in herbs such as alfalfa, horsetail, pepper, lemongrass, nettle, sage, hops, and plantain.

Vitamin A is involved in a number of metabolic processes occurring in human body. It plays an important role in the regulation of protein biosynthesis and ensures the stability of cell membranes. The connection is necessary for the formation of bone tissue, as well as enamel and dentin. Thanks to him, the fat reserves necessary for a person are formed.

Note:It has been known since ancient times that liver consumption improves visual acuity and helps prevent or cure night blindness.

Retinol is necessary for adequate photoreception (perception of light); it takes part in the biosynthesis of retinal pigment. The most important carotenoids prevent cataracts and significantly reduce the likelihood of degeneration. yellow spot"- a pathology that is one of the main causes of blindness.

Vitamin A is one of the most effective natural antioxidants. It minimizes the harmful effects of free radicals, which allows the use of retinol and carotenoids for the prevention and treatment (as part of complex therapy) of oncological diseases. In clinical studies, it has been proven that b-carotene reduces the likelihood of recurrence of malignant neoplasms after surgery.

The antioxidant effect prevents the development of a number of serious pathologies heart and blood vessels.

Vitamin A is able to increase the serum concentration of high density lipoproteins necessary for the body.

The carotenoid lycopene, which is found in large quantities in tomatoes, prevents the deposition of cholesterol on the vascular walls, thus protecting a person from its dangerous consequences. This provitamin also reduces the likelihood of developing malignant and breast cancer, as well as prostate cancer.

The state of non-specific depends largely on vitamin A. The compound is able to increase the body's resistance against infectious agents of a bacterial and viral nature (the phagocytic activity of leukocytes is significantly increased).

Sufficient intake of vitamin A with food reduces the likelihood of developing colds, as well as infections of the genitourinary and respiratory systems and organs of the gastrointestinal tract.

Children who eat well and regularly receive retinol and carotenoids in the right amount are much easier to tolerate "" and.

Continuous presence in serum is sufficient high level retinol significantly increases the life expectancy of patients suffering.

Vitamin A is actively involved in the process of regeneration of the epithelial layer of the skin and mucous membranes. Its preparations are widely used in the treatment of any (, etc.), as well as skin damage due to mechanical injuries or burns. Due to the stimulation of the collagen biosynthesis process, retinol provides the fastest healing, greatly reducing the risk of developing secondary infectious complications. Vitamin A significantly improves the quality of tissue that is newly formed at the site of significant damage.

Note:many modern cosmetic preparations include retinoid substances, which are nothing more than synthetic analogues of vitamin A. Retinoid creams are very good for sunburn.

The beneficial effect of retinol on epithelial cells provides an improvement functional activity bronchi and lungs. Receiving vitamin A preparations for patients can speed up recovery in such pathologies of the digestive tract as peptic ulcer and colitis (inflammation of the mucous membranes of the walls of the large intestine).

Retinol is one of the most important organic compounds needed for normal prenatal development future child.

Women who are preparing to become mothers are advised to consume enough vitamin A to improve the nutrition of the fetus and reduce the likelihood of having an underweight baby.

For pregnant women, the daily intake of retinol should be 750-770 micrograms. For nursing mothers, the norm recommended by Russian doctors is higher - 1200-1300 mcg.

Important: during childbearing, you can not consume more than 6000 IU per day, because high doses have a teratogenic effect on the fetus. For the same reason, during pregnancy, women are categorically contraindicated in fish oil.

How much vitamin A is required per day?

The average intake of vitamin A for an adult is 3300 IU (1000 mcg) per day. Against the background of pathologies caused by hypovitaminosis A, it is recommended to increase consumption by 3 times (up to 10,000 IU).

Important:climatic conditions can affect the body's need for vitamin A. Cold weather has no effect on retinol metabolism, but a hot climate makes its own adjustments: the need for this vitamin increases significantly.

Babies in their first year of life need 400 micrograms of retinol per day. Children from 1 to 3 years old need 450 mcg of the vitamin, those aged 4 to 6 years need 500 mcg, and from 7 to 10 years old 700 mcg per day.

For teenagers, the rules are the same as for adults.

Note:the need is reduced in women who take birth control pills.

Hypovitaminosis: causes and symptoms

Plasma vitamin A levels are considered insufficient if they are below 0.35 µmol/L.

Even at a level of 0.70-1.22 µmol / l, the amount of retinol in its main “storage”, i.e., in the liver, is noticeably reduced.

The main reasons for the development of hypovitaminosis include:

For the full assimilation of vitamin A, it is necessary to consume a sufficient amount of fat and complete protein. It must be present in food, the absence of which makes it difficult to absorb retinol.

Important:hypovitaminosis A is often observed in vegetarians who do not replace animal products with the necessary amount of high-grade vegetable protein.

The characteristic manifestations of hypovitaminosis include:

• increased temperature sensitivity;
• lowering the pain threshold;
• early aging of the skin (the appearance of wrinkles);
• dryness and peeling of the skin;
• redness of the eyelids;
• feeling " foreign body"or" sand "in the eyes;
• accumulation of mucus and the formation of crusts in the corners of the eyes;
• urinary incontinence (sphincter weakness);
• hyperesthesia (pathologically high degree of sensitivity) of tooth enamel;
• deterioration of erectile function;
• early ejaculation.

A very characteristic manifestation of retinol deficiency is hemeralopia - a significant deterioration in vision at dusk.

Consequences of vitamin A deficiency:

• xerophthalmia (dryness of the cornea of ​​​​the eyes);
• clouding of the cornea;
• precancerous pathologies and skin cancer;
• atrophic gastritis;
• intestinal inflammation;
• pancreatitis;
• decrease in sexual desire;
• mastopathy;
• malignant tumors of the mammary glands;
• gynecological diseases (etc.);
• cachexia (exhaustion);
• anemia (anemia);
• frequent respiratory infections;
• cystic formations of the liver;
• insomnia.

Indications for taking vitamin A

Vitamin A is prescribed orally, for injection (IM) or for topical application, if diagnosed:

• pathology of the skin and mucous membranes;
• inflammation of the cornea and conjunctiva of the eyes;
• burns, fractures and other injuries (to accelerate regeneration).

Mild and moderate hypovitaminosis require doses up to 33,000 IU for adult patients and from 1,000 to 5,000 for children. For skin diseases, the dosages are higher - 50000-100000 and 5000-10000 IU, respectively.

Hypervitaminosis

Important:vitamin A has a toxic effect on the body when consumed 25,000 IU per day.

Symptoms of hypervitaminosis:

• pain in the abdominal region;
• hepatosplenomegaly;
• alopecia;
• arthralgia;
• "Zaedy" in the corners of the mouth;
• delay of menstruation;
• dry skin;
• increased fragility and thickening of the nail plates.

Important:a lack of zinc leads to a violation of the absorption of retinol.

The combination of vitamin A and ethanol causes more significant liver damage than alcohol exposure.

Vitamin A It is a fat-soluble substance that the body needs for normal functioning. In medical practice, it is also called "children's", as it regulates growth processes. However, it is necessary for all people without exception. The fact is that vitamins A are also responsible for strengthening the immune system, tissue regeneration. Organic matter is almost not produced by organs. Therefore, all adults should know which foods contain the most of it. In addition, we will consider the symptoms of beriberi (vitamin deficiency), the daily norm and the value of the component in life processes. Finally, let's cover a few interesting facts, which allow you to restore youthfulness to the skin, strengthen nails, hair and improve vision. You can be sure that they are closely related to the content of the specified component in the liver, because it is in this organ that it accumulates.

What contains and why do we need Vitamin A?

Unfortunately, the substance is not synthesized by the body. But it is not necessary to replenish vitamin A reserves daily. Fortunately, this component, like carotene, has good property- can accumulate in the human liver for a long time. The reserve can be kept throughout the year. At the same time, it is more expedient to replenish stocks in the summer, since during this period of time the greatest amount of fruits and vegetables that contain organic matter grows.
As for the appointment, it should be noted that group A vitamins are involved in:

• the formation of amino acids;
• growth of bones, teeth and hair;
• skin rejuvenation;
• protection of the epidermis;
• metabolic processes;
• restoration of the immune system;
• eye adaptation.

In addition to this, vitamins have antioxidant properties, hence preventing cardiovascular disease. Moreover, experts have found that intensive consumption of food rich in vitamin A can prolong the lives of even AIDS patients.

As already mentioned, vitamins of group A can accumulate in our liver for a long time. For this reason, there is no need to torture yourself with an excess of products containing the component. Below is the daily requirement (norm) in mcg:

1. For adults - up to 1000;
2. For pregnant women - up to 1200;
3. For children - 400-600;
4. For nursing mothers - 1400.

An excess of vitamin A in a person's blood can manifest itself in different ways. As a rule, gums bleed and blood vessels burst. If you have overindulged on dairy products, fish, or carrots, it is likely that your nose bleeds for this very reason. However, with an excess of the fat-soluble component, dizziness can also be observed!

There are many sources of vitamin A. It is found in both plant and animal products. Most found in carrots, rose hips, hawthorn, mountain ash, tomatoes, apricots, zucchini, broccoli and Bulgarian. Also, a high concentration is observed in persimmon, dill, butter, melon and peaches.

As for animal products, vitamin A is observed in egg yolk, beef liver, caviar, fish, cheese and margarine. However, fish oil contains the most component. Actually, for this reason, in winter, doctors prescribe Omega amino acids, which are found in fish.

As clinical studies show, with a lack of "children's vitamin" there is exhaustion, insomnia and weakened erection. In addition, there is no appetite, eyesight falls and hair falls out. In some cases, "night blindness" overtakes, that is, poor adaptation of the eyes to the dark. If the body of children lacks a component, growth retardation and dry skin are observed. Often wrinkles appear and the epidermis on the palms cracks. Also, experts assure that the absence of this substance in the liver can lead to infertility and conjunctiva of the eyes. Based on this, we can conclude that vitamins of group A are vital for a person in order to normally cope with negative factors. environment!

To this day, everything beneficial features this component has not been fully explored. Nevertheless, we will give a list of several facts that will convince you of the relevance of products containing the "elixirs of life" group A. And so:

1. It is worth noting that vitamins A must be consumed in abundance by people who constantly work at a computer. The fact is that this substance improves the adaptability of the eyes to poorly lit rooms. And even at dusk. Experts recommend eating carrots often for people who load their eyes daily. Only with sour cream, as the vegetable juice itself is not absorbed!
2. People who are not deficient in vitamins have an improved response, attention, and resistance to infections.
3. With the use of vitamins A, the body's resistance to cancer improves.
4. Many toothpastes contain this component, as it improves the condition of the gums.
5. To strengthen the skin and hair, cosmetologists advise paying attention to natural cosmetics that contain a component. It is worth noting that vitamins A resist aging!

Finally, I would like to add that in our world there are many products about the benefits of which we know too little. We advise you to read the most useful fruits in order to properly take care of your health, youth and beauty!